Neuroprosthesis gives rats the ability to 'touch' infrared light
Researchers have given rats the ability to "touch" infrared light, normally invisible to them, by fitting them with an infrared detector wired to microscopic electrodes implanted in the part of the mammalian brain that processes tactile information. The achievement represents the first time a brain-machine interface has augmented a sense in adult animals, said Duke University neurobiologist Miguel Nicolelis, who led the research team.
The experiment also demonstrated for the first time that a novel sensory input could be processed by a cortical region specialized in another sense without "hijacking" the function of this brain area said Nicolelis. This discovery suggests, for example, that a person whose visual cortex was damaged could regain sight through a neuroprosthesis implanted in another cortical region, he said.
Although the initial experiments tested only whether rats could detect infrared light, there seems no reason that these animals in the future could not be given full-fledged infrared vision, said Nicolelis. For that matter, cortical neuroprostheses could be developed to give animals or humans the ability to see in any region of the electromagnetic spectrum, or even magnetic fields. "We could create devices sensitive to any physical energy," he said. "It could be magnetic fields, radio waves, or ultrasound. We chose infrared initially because it didn't interfere with our electrophysiological recordings."
Nicolelis and colleagues Eric Thomson and Rafael Carra published their findings February 12, 2013 in the online journal Nature Communications. Their research was sponsored by the National Institute of Mental Health.
"The philosophy of the field of brain-machine interfaces has until now been to attempt to restore a motor function lost to lesion or damage of the central nervous system," said Thomson, first author of the study. "This is the first paper in which a neuroprosthetic device was used to augment function—literally enabling a normal animal to acquire a sixth sense."
The mammalian retina is blind to infrared light, and mammals cannot detect any heat generated by the weak infrared light used in the studies. In their experiments, the researchers used a test chamber that contained three light sources that could be switched on randomly. Using visible LED lights, they first taught each rat to choose the active light source by poking its nose into an attached port to receive a reward of a sip of water.
After training the rats, the researchers implanted in their brains an array of stimulating microelectrodes, each roughly a tenth the diameter of a human hair. The microelectrodes were implanted in the cortical region that processes touch information from the animals' facial whiskers.
Attached to the microelectrodes was an infrared detector affixed to the animals' foreheads. The system was programmed so that orientation toward an infrared light would trigger an electrical signal to the brain. The signal pulses increased in frequency with the intensity and proximity of the light.
The researchers returned the animals to the test chamber, gradually replacing the visible lights with infrared lights. At first in infrared trials, when a light was switched on the animals would tend to poke randomly at the reward ports and scratch at their faces, said Nicolelis. This indicated that they were initially interpreting the brain signals as touch. However, over about a month, the animals learned to associate the brain signal with the infrared source. They began to actively "forage" for the signal, sweeping their heads back and forth to guide themselves to the active light source. Ultimately, they achieved a near-perfect score in tracking and identifying the correct location of the infrared light source.
To ensure that the animals were really using the infrared detector and not their eyes to sense the infrared light, the researchers conducted trials in which the light switched on, but the detector sent no signal to the brain. In these trials, the rats did not react to the infrared light.
A key finding, said Nicolelis, was that enlisting the touch cortex for light detection did not reduce its ability to process touch signals. "When we recorded signals from the touch cortex of these animals, we found that although the cells had begun responding to infrared light, they continued to respond to whisker touch. It was almost like the cortex was dividing itself evenly so that the neurons could process both types of information.
This finding of brain plasticity is in contrast with the "optogenetic" approach to brain stimulation, which holds that a particular neuronal cell type should be stimulated to generate a desired neurological function. Rather, said Nicolelis, the experiments demonstrate that a broad electrical stimulation, which recruits many distinct cell types, can drive a cortical region to adapt to a new source of sensory input.
A major technical achievement that could enable the creation of a variety of neuroprosthetic devices was the laboratory's ability, announced last December, to record brain signals from almost 2,000 brain cells at once, an unprecedented number said Nicolelis. Ultimately, the researchers hope to record the electrical activity produced simultaneously by 10,000 cortical neurons. Such massive brain recordings will enable more precise control of motor neuroprostheses—such as those being developed by the Walk Again Project [www.walkagainproject.org]—to restore motor control to paralyzed people, Nicolelis said.
The Walk Again Project has recently received a $20 million grant from FINEP, a Brazilian research funding agency to allow the development of the first brain-controlled whole body exoskeleton aimed at restoring mobility in severely paralyzed patients. A first demonstration of this technology is expected to happen in the opening game of the 2014 Soccer World Cup in Brazil.
Expanding sensory abilities could also enable a new type of feedback loop to improve the speed and accuracy of such exoskeletons, said Nicolelis. For example, while researchers are now seeking to use tactile feedback to allow patients to feel the movements produced by such "robotic vests," the feedback could also be in the form of a radio signal or infrared light that would give the person information on the exoskeleton limb's position and encounter with objects.
Journal reference: Nature Communications
Provided by Duke University
- Monkeys feel, move virtual objects using only their brains (w/ video) Oct 05, 2011 | not rated yet | 0
- Monkey's Thoughts Make Robot Walk from Across the Globe Jan 17, 2008 | not rated yet | 0
- Body suit may soon enable the paralyzed to walk Oct 06, 2011 | not rated yet | 0
- Robot arm improves performance of brain-controlled device Dec 14, 2010 | not rated yet | 0
- Will we hear the light? Surprising discovery that infrared can activate heart and ear cells Mar 28, 2011 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Pressure-volume curve: Elastic Recoil Pressure don't make sense
16 hours ago From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
Marie Curie's leukemia
May 13, 2013 Does anyone know what might be the cause of Marie Curie's cancer
- More from Physics Forums - Medical Sciences
More news stories
For combat veterans suffering from post-traumatic stress disorder, 'fear circuitry' in the brain never rests
Chronic trauma can inflict lasting damage to brain regions associated with fear and anxiety. Previous imaging studies of people with post-traumatic stress disorder, or PTSD, have shown that these brain regions can over-or ...
Neuroscience 18 hours ago | 5 / 5 (1) | 0 |
The neural machinery underlying our olfactory sense continues to be an enigma for neuroscience. A recent review in Neuron seeks to expand traditional ideas about how neurons in the olfactory bulb might encode information about ...
Neuroscience May 17, 2013 | not rated yet | 0 |
(Medical Xpress)—What if the quality of your work depends more on your focus on the piano keys or canvas or laptop than your musical or painting or computing skills? If target users can be convinced, they ...
Neuroscience May 17, 2013 | 3.7 / 5 (3) | 0 |
Neurological disorders can have a devastating impact on the lives of sufferers and their families.
Neuroscience May 17, 2013 | 5 / 5 (1) | 0 |
If you're a left-brain thinker, chances are you use your right hand to hold your cell phone up to your right ear, according to a newly published study from Henry Ford Hospital in Detroit.
Neuroscience May 16, 2013 | 2 / 5 (2) | 0 |
An increasing number of U.S. children are experiencing gastrointestinal issues that require interventions to resolve, according to research presented at Digestive Disease Week (DDW).
9 hours ago | not rated yet | 0 |
The latest makeover to a massive psychiatric tome honored by some, reviled by others and even called the "Bible" of mental disorders is being released Saturday with a host of new changes.
6 hours ago | not rated yet | 0
A new case of the deadly coronavirus has been detected in Saudi Arabia where 15 people have already died after contracting it, the health ministry announced on Saturday on its Internet website.
7 hours ago | not rated yet | 0
Big names in medicine are set to give an upbeat assessment of the war on AIDS on Tuesday, 30 years after French researchers identified the virus that causes the disease.
17 hours ago | 5 / 5 (1) | 0
A ground-breaking advance in colonoscopy technology signals the future of colorectal care, according to research presented today at Digestive Disease Week(DDW). Additional research focuses on optimizing the minimal withdrawal ...
9 hours ago | 5 / 5 (1) | 0